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Remove empty elements from an array in Javascript
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Operation on every pair of element in a list
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233
Check out product() in the itertools module. It does exactly what you describe.
import itert...
Select multiple columns in data.table by their numeric indices
...llowing all just work:
library(data.table)
dt <- data.table(a = 1, b = 2, c = 3)
# select single column by index
dt[, 2]
# b
# 1: 2
# select multiple columns by index
dt[, 2:3]
# b c
# 1: 2 3
# select single column by name
dt[, "a"]
# a
# 1: 1
# select multiple columns by name
dt[, ...
How to get row from R data.frame
...is, for example:
#Add your data
x <- structure(list(A = c(5, 3.5, 3.25, 4.25, 1.5 ),
B = c(4.25, 4, 4, 4.5, 4.5 ),
C = c(4.5, 2.5, 4, 2.25, 3 )
),
.Names = c("A", "B", "C"),
class = "da...
Ruby max integer
... big they can be.
If you are looking for the machine's size, i.e. 64- or 32-bit, I found this trick at ruby-forum.com:
machine_bytes = ['foo'].pack('p').size
machine_bits = machine_bytes * 8
machine_max_signed = 2**(machine_bits-1) - 1
machine_max_unsigned = 2**machine_bits - 1
If you are look...
Can't install RMagick 2.13.1. Can't find MagickWand.h.
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32 Answers
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Memoization in Haskell?
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259
We can do this very efficiently by making a structure that we can index in sub-linear time.
B...
What is the difference between tinyint, smallint, mediumint, bigint and int in MySQL?
...ation:
MySQL
Postgres
Oracle (they just have a NUMBER datatype really)
DB2
Turns out they all use the same specification (with a few minor exceptions noted below) but support various combinations of those types (Oracle not included because it has just a NUMBER datatype, see the above link):
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Regular expression search replace in Sublime Text 2
I'm looking to do search replace with regular expressions in Sublime Text 2. The documentation on this is rather anemic. Specifically, I want to do a replace on groups, so something like converting this text:
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